In this study, photocatalytic degradation of Safranin-O dye in wastewater has been investigated as an organic pollutants by UV irradiation and antimony trioxide as catalyst. All results has been analyzed using UV–vis spectrophotometer. The project include study the initial dye concentration, light intensity, catalyst loading, the effect of intensity of light, and effect of temperature in order to reach to the optimum operational conditions to created the beast photodegradation efficiency of dye. The highest photocatalytic degradation of Safranin-O dye was observed at 0.10 gm/100cm3 of dosage mass of antimony tri oxide and 20ppm of Safranin-O dye. photocatalytic degradation of Safranin-O dye was favorable in the 9 mW/cm2 light intensity. The percentage efficiency of degradation Safranin-O dye equals 97.46%. The activation energy has been calculated it was found equal to 30.48 ±1 kJ.mol-1.